Main purpose of this research is to show how important social media is for advertising. Guerrilla marketing is a form of advertising used to introduce new products or service, but without great costs. It envokes customer attention and it is usually presented with something different and interesting. Guerrilla marketing is perfect for small enterprises, but even the big ones tend to use it. Development of social media caused changes in marketing activites. Recognizing importance and influence of social media is crucial for any business because social media has it's own benefits. New technology has changed consumer behavior, as well as their expectations. On the other hand, because of them companies now have new tools of communication with their target audience, who they can trace faster than ever.